/Engine/Source/Runtime/Engine/Classes/Kismet/KismetMathLibrary.h
Easing between A and B using a specified easing function
static FRotator REase ( FRotator A, FRotator B, float Alpha, bool bShortestPath, [TEnumAsByte](API\Runtime\Core\Containers\TEnumAsByte)< [EEasingFunc::Type](API\Runtime\Engine\Kismet\EEasingFunc__Type) > EasingFunc, float BlendExp, int32 Steps )